Method for authentication by chemical marking or tracing of an object or a substance

ABSTRACT

The invention concerns a method for authenticating different objects or substances to be identified comprising at least two phases: during an initial phase, selecting a plurality of chemical markers, assigning to and incorporating in each of the objects or substances a combination of markers, establishing an identification and/or authentication code (blocks  2, 11 ), storing in memory data or code for identifying and/or authenticating all the objects or substances and annex data; during an identification and/or authentication phase: a spectrophotometric analysis so as to determine a specific scanned code of the presence or absence of the markers (blocks  3, 4 ), identifying the object or the substance by comparing the scanned code and the identification and/or authentication codes (block  6 ). The invention is particularly applicable to fighting against counterfeiting, to automatic sorting, and the like.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention concerns a method for authenticating objects orsubstances using chemical marking or tracing. It applies moreparticularly but not exclusively to the fight against counterfeiting, toautomatic sorting.

2. Description of the Prior Art

As a general rule, numerous objects or substances whether in transit oron sale are identified by means of a bar code. With this code it ispossible to define products but it is not sufficient for theirauthentication i.e. for certifying after analysis that the object orsubstance is indeed the one defined by the bar code.

In an attempt to solve this problem, methods integrating a chemicalmarker into objects or substances have been developed. However, it isnecessary to have recourse to laboratories to perform analyses anddetect counterfeited products: this procedure is far too time-consumingand laborious.

As for the solution which consists of developing analytical equipmentspecific to each product, this solution is not economically viable.

OBJECT OF THE INVENTION

The object of the invention is to solve these drawbacks by proposingthat only one apparatus is used for a multiplicity of products.

SUMMARY OF THE INVENTION

For this purpose, it proposes an authentication method for differentobjects or substances to be identified, comprising at least the twofollowing successive phases:

-   -   An initial phase comprising:        -   choosing a plurality of chemical markers which, when excited            by an incident light ray, emit energy radiations whose            frequency spectra can be distinguished from one another and            with respect to the objects or substances in which they are            intended to be incorporated,        -   allocating to and then incorporating in each of the objects            or substances a previously chosen combination of markers,            the combination being different to those allocated to other            objects,        -   determining an authentication code using parameters relating            to the presence or absence of markers in the allocated            combinations,        -   storing, in a computer memory system, the authentication            code of all the objects or substances, and related data            corresponding to these objects or these substances,        -   allocating to the object or substance an identification            code, such as a bar code or similar, this identification            code possibly being associated with the object, with the            substance, with its recipient and/or its packaging,        -   storing, in the memory of said system, the identification            codes for each of the objects,        -   defining a correspondence between the identification codes            and authentication codes.    -   An identification and authentication phase by said system, this        phase comprising:        -   theoretical identification of the object or substance by            reading the identification code associated with the object,        -   spectrophotometer analysis of at least part of the object or            substance so as to detect said above parameters, in            particular the presence or absence of markers, and            determination of the authentication code of the object or            substance,        -   authentication of the object if the theoretical            identification code corresponds to the authentication code,        -   emission of a validation signal when correspondence is            detected or of an alert signal when the authentication code            does not correspond to the identification code.

In this method, the spectrophotometric analysis phase may comprise thefollowing steps:

-   -   irradiation of the marked object or substance using a light beam        with wide frequency spectrum,    -   sending the waves transmitted or reflected by the object or        substance, after emission by a generator, onto a dispersing        element which deflects the waves so as to obtain a light        spectrum of the light intensity at different zones of the        spectrum corresponding to different wavelength ranges, or onto        specific or dedicated filters,    -   detecting the light intensity in each zone,    -   comparing this intensity with one or more threshold values        specifically allocated to this zone and which are stored in        memory as being said above parameters,    -   the result of this comparison contributing towards determining        the authentication code of the object.

Advantageously, the determination of the spectrum zones to be analysed,and of the different parameters allocated to each of these zones, may bemade by the system using the identification data. This solution providesimproved reliability of results and considerably reduces the requiredpower of processing means.

The parameters relating to the presence or absence of markers in theallocated combination and used for determining an identification and/orauthentication code particularly comprise:

-   -   the presence or absence of fluorescence,    -   a fluorescence time that is greater or less than at least one        threshold value,    -   the presence or absence of a peak at a predetermined wavelength        and optionally the amplitude and/or width of this peak,    -   emission peak heights corresponding to a concentration of        markers that is greater or less than one or more predefined        threshold values.

To increase the number of possible combinations, differentconcentrations of markers may be used to obtain rays of differentintensity.

Also, to overcome any optical factors likely to disturb the reading andsubsequent spectrophotometric analysis, the invention proposes twomeasures which may be used separately or in combination.

The first measure consists of servo-controlling the light intensityemitted by the light radiation generator in relation to the differencebetween the value of the light intensity detected over a predeterminedfrequency range that is not affected by the presence of the markers, anda predetermined set value.

The second measure consists of incorporating in the object and/orsubstance one or more calibration markers used by the computer systemfor correction or calibration purposes so as to overcome noise derivedfor example from the composition of the substance or object, fromvariations in positioning such as angle of incidence and distance to theobject, or from transparent matter surrounding this substance or object.

These two measures prove to be essential when several intensity levelsare used as parameters.

According to one variant, chemical marking may be made via a label, aninsert or any other medium containing the marker or markers.

Advantageously, this label may comprise a reflective zone coated with atransparent layer containing markers. With this solution it is possibleto conduct reflection spectrophotometry which considerably reducesenergy losses.

The authentication data may comprise the combination of chosen markers,the wavelengths of characteristic rays, their intensity, possiblefluorescence time . . .

It is therefore not necessary to cover all wavelengths, it is sufficientto analyse the ranges of values corresponding to the expected rays whichare identified using the identification code in order to verify theirpresence or absence without taking into account the zones locatedoutside these ranges.

To conduct authentication, the operator performing the analysis does notneed to know the theoretical identity of the object or substance sinceit is provided by the bar code directly to the computer systemperforming data comparison.

Said method may be used in the fight against counterfeiting, but mayalso be applied to automatic sorting. For example, when recyclingplastic, it could be considered to use a combination of markers per typeof plastic or per grade of plastic enabling subsequent sorting per typeor per grade once authentication has been carried out.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing a device using the method of the invention,the waves being transmitted;

FIG. 2 is a functional diagram of the method of the invention;

FIG. 3 is a diagram showing a device using the method of the invention,the waves being reflected;

FIG. 4 is a diagram showing a device using the method of the invention,the waves being reflected onto a label.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the example in FIG. 1, it is the waves which are transmitted througha substance containing a combination of markers and more precisely ontoa sample possibly diluted in a solution which are analysed.

It is to be noted that this type of analysis can also be made on objectswhose material so permits, or directly on the substance through itsrecipient.

In this example the identification and authentication device using themethod of the invention comprises a spectrophotometer comprising:

-   -   a generator of light radiation with long frequency spectrum and        adjustable intensity using a light source 4 supplied by a        power-adjustable electric current generator 6; a collimator 2 in        whose axis a lens 5 is positioned,    -   a product sample 8 contained in a transparent recipient 9        positioned in the optical axis of the light generator,    -   a dispersing element 1 positioned in said axis on the side of        the recipient 9 located opposite the light generator; this        dispersing element 1 (prism or diffraction network) decomposes        the light ray in relation to frequency, producing a spectrum,    -   spectrum detection means, here a charge transfer detector array        3 to detect the radiations emitted at different spectral levels        by the dispersing element 1 and to transmit a digital signal        representing the detected spectrum to an electronic system.

As mentioned previously, the light source 4 is a source with widefrequency spectrum. It may consist of arc lamps (Xenon type) or of alight bulb generating a white light. Optionally, it may consist of aplurality of laser radiation sources specifically chosen in relation tothe type of the chemical markers used, a mixer then being used to mixthe different radiations emitted by these sources.

The lens 5 may for example consist of an achromatic doublet.

Evidently, the electric current generator 6 may also be used to supplythe electronic circuits associated with the spectrophotometer.

In this example, the detector array 3 comprises a cell C located at aposition of the spectrum that is not affected by the presence ofchemical markers.

This cell C emits a detection signal applied (after amplification) tothe input of a subtractor S whose second input receives a calibratedvoltage VC. The output of this subtractor S is applied to a poweramplifier AP which pilots the generator 6 so that the output of thesubtractor S is maintained at a constant value, preferably equal tozero.

With this arrangement, it is ensured that the level of light intensityreceived by cell C is constant. This overcomes disturbances which maycause variations in the light intensity of the radiation transmittedthrough sample 8.

According to the invention, the light source is associated with a barcode reader 12 which emits light radiation (laser for example) in thedirection of a bar code 11 carried by recipient 9. This reader 12comprises a receiver enabling detection of the radiation reflected bythe bar code. An electronic circuit processes the data received by thisreceiver and generates a digital signal representing this bar code to besent to the electronic system E.

The electronic system comprises a processor P (indicated by the dashedline) associated with means for memorising a database of identificationcodes BC, a database of authentication codes BA and a managementprogramme for the various processing operations PG, and with display andsignalling means AF.

This processor P is designed so as to conduct theoretical identification(block B1) of recipient 9 using the signal delivered by the bar codereader 12, from the database of identification codes BC. Oncetheoretical identification has been made, processor P determines thespectrum zones to be investigated (block B2). For this purpose, inaddition to the readout identification code, it uses the correspondingauthentication code by means of a correspondence table TC between thetwo databases BC, BA. The processor P then analyses (block B3) thespectrum zones previously determined through the signal provided by thedetector array 3.

If a calibration marker is used, this signal may be corrected (block B4)before analysis using the digital signal produced by the detectorcorresponding to this calibration marker.

The processor P then determines (block B5) the detected authenticationcode which it compares (block B6) with the predetermined identificationcode. If there is agreement between these two codes, the processor emitsa validation signal SV. If not, the processor emits an alarm signal SA.

The method of the invention used by the device illustrated FIG. 1,comprises the following phases (FIG. 2):

-   -   An initial phase comprising:        -   choosing markers in relation to their respective suitability            and with respect to the substance,        -   adding these markers at different concentrations to said            substance,        -   determining the authentication codes formed of binary            figures representing the presence or absence, even the            concentration of the markers, these codes being stored in            memory in the electronic system E,        -   allocating, to each of these codes, a substance identified            by a bar code 11.    -   An identification and/or authentication phase comprising:        -   reading the bar code 11, located on the recipient of the            marked substance by means of the bar code reader 12 and            emitting a specific signal containing an identification code            of said substance (block 1),        -   transmitting said signal to the electronic system E which            identifies this identification code (block 2),        -   spectrophotometric analysis comprising:            -   irradiation of the substance using the ray source 4,            -   transmission of the transmitted waves onto the                dispersing element 1 which deflects them differently in                relation to their wavelength,            -   obtaining a spectrum of transmitted radiation by means                of the planar waves so deflected, which, in a detection                zone consisting of the series of charge transfer                detection arrays 3, give a succession of images of the                source (block 3),            -   sampling this spectrum then converting the analogue                signal into a digital signal having a predetermined                digital frame (block 4),            -   windowing in relation to the wavelength ranges indicated                in the authentication data stored in memory and                extracted through identification of the bar code, so as                only to give consideration to the presence of absence or                rays characteristic of the markers, which then                determines a readout code (block 5),            -   comparison of the data or authentication code with the                experimental data or readout code so as to conduct                authentication of the substance (block 6),        -   visual display of the result, for example on a screen 13            and/or audibly:            -   successful authentication if the authentication codes                and readout code tally (block 7),            -   alert signal in the event of non-authentication if there                is disagreement between the authentication codes and the                readout code (block 8).

FIG. 3 illustrates an analysis using waves reflected on at least part ofan object or substance 14.

In this case, the dispersing element 1 is located on the axis of thereflected wave.

The method is the same as described above for the example in FIG. 1.

FIG. 4 illustrates a variant of the example in FIG. 3. Here the markersare not directly integrated in the object or substance 14 but areapplied by means of a film, a transparent varnish on a label 15 which isaffixed to the object to be marked.

The method is the same as described above for the example in FIG. 1.

For a better analysis result, the label may be reflective.

In addition, the use of a label free of any marker and optionally coatedwith a film or varnish used for applying markers may, when processingdata, enable the elimination of corresponding signals and simplifyanalysis. The marked label then the blank label are irradiated afterwhich, during data processing, the spectrum data of the blank label aresubtracted from the spectrum data for the marked label.

When fluorescent markers are used, it can be considered to conduct asecond measurement after a time δt to verify fluorescence time.

The tracers used may be organic or inorganic. They may contain rareearths such as dysprosium, europium, samarium, yttrium . . .

Some markers used and their characteristics are given as examples in thetable below.

They are commercially available from companies such as BASF, Bayer,Glowburg, Lambert Riviere, Phosphor Technology, Rhodia, SCPI, . . .

Excitation wavelength Wavelength of emission peak Marker λ_(ex) +Δλ_(1/2) λ_(emax) + Δλ_(1/2) (nm) A 300 ± 40 480 ± 6  572 ± 6  B 300 ±40 562 ± 10 601 ± 6  C 335 ± 35 470 ± 85 D 365 ± 70 480 ± 90 E 350 ± 20612 ± 3  F 380 ± 45 480 ± 75 G 365 610 ± 50

It is to be noted that the markers are not limited to commerciallyavailable markers, they may be synthesised by total synthesis or derivedfrom commercial markers.

1. A method for identifying and authenticating different objects orsubstances, the method using a computer system coupled tospectrophotometry means, said method comprising at least the twofollowing successive phases: an initial phase comprising: choosing aplurality of chemical markers which, when excited by an incident lightray, emit energy radiations whose frequency spectra can be distinguishedfrom one another and with respect to objects and substances in whichthey are intended to be incorporated, allocating then incorporating, ineach of the objects or substances, a combination of markers that isdifferent than combinations allocated to the other objects orsubstances, determining an authentication code for each of the objectsor substances defined using parameters comprising at least the presenceor absence of markers in the allocated combination of markers, storing,a memory of the computer system, the authentication code of all theobjects or substances and of related data corresponding to said objectsor substances, allocating an identification code to each of said objectsor substances, said identification code being associated with at leastone of said objects or substances and a recipient or packaging for theat least one of said objects or substances, storing, in the memory ofsaid system, the identification codes for each of the objects orsubstances, defining a correspondence between the identification codesand the authentication codes, an identification and authentication phaseby said system comprising: determining a theoretical identification codefor one of said objects or substances by reading the identification codeassociated with said one of the objects or substances and the recipientor packaging for the object or substance, spectrophotometric analyzingat least part of the one object or substance so as to detect said aboveparameters, and determining an experimental authentication code of theone object or substance, authenticating said one object or substance ifthe theoretical identification code corresponds to the experimentalauthentication code, emitting a validation signal if a correspondence isdetected or an alert signal if the experimental authentication code doesnot correspond to the theoretical identification code, wherein saidspectrophotometric analysis comprises the following steps: determiningzones of the spectrum to be analysed and the different parametersallocated to each of these zones using said above identification codes,irradiating the one object or substance with a light ray emitted by agenerator, sending transmitted or reflected waves onto a dispersingelement which deflects them so as to obtain a light spectrum of thelight intensity in said zones of the spectrum corresponding to differentwavelength ranges, detecting the light intensity in said zone, comparingthe detected light intensity with one or more threshold valuesspecifically allocated to said zone and which are recorded in memory asbeing said above parameters, and using the result of this comparison inthe determination of the experimental authentication code of the object.2. Method as in claim 1, comprising servo-controlling the lightintensity emitted by the light radiation generator in relation to thedifference between the value of the detected light intensity, over apredetermined frequency range not affected by the presence of themarkers, and a predetermined set value.
 3. Method as in claim 1,comprising the incorporation into the object and/or substance of one ormore calibration markers by means of which the computer system conductscorrections and/or calibration so as to overcome noises possiblyderiving from the composition of the substance or object, fromvariations in positioning such as the angle of incidence of theradiation emitted by the light ray generator, and distance to theobject.
 4. Method as in claim 1, wherein said above generator of lightradiation comprises a light source with wide frequency spectrum such asan arc lamp or a light bulb generating a white light.
 5. Method as inclaim 1, wherein said generator of light radiation comprises a pluralityof laser radiation sources specifically chosen in relation to the typeof chemical markers used, and a mixer to mix the different radiationsemitted by these sources.
 6. Method as in claim 1, wherein saidprocessing of data from spectrophotometric analysis comprises thefollowing steps: sampling of the spectrum, conversion of the analoguesignal into a digital signal having a predetermined frame, windowing inrelation to the wavelength ranges indicated in the authentication datastored in memory, and extracted by identifying the bar code, so as todetermine a readout code with said above parameters, comparison ofauthentication data with the experimental data or readout code,displaying of the result visually and/or audibly so as to indicate:successful authentication if the authentication codes and the readoutcode coincide, an alert in the event of non-authentication if theauthentication codes and the readout code do not tally.
 7. Method as inclaim 1, wherein said marking is made via a medium containing the markeror markers, this medium being a label or an insert.
 8. Method as inclaim 7, wherein said medium containing the marker or markers isreflective.
 9. Method as in claim 7, wherein a blank medium free of anymarker is added and also irradiated then, during data processing, thespectrum data of the blank medium are subtracted from the spectrum dataof the marked medium so as to eliminate corresponding signals and tosimplify analysis.
 10. Method as in claim 9, wherein, during dataprocessing, the spectrum data of the object or substance free of markersare subtracted from the spectrum data of the marked object or substance.11. Method as in claim 1, wherein said combination of markers comprisesat least one fluorescent marker.
 12. Method as in claim 9, wherein saidparameters also comprise the duration of the light emission of thesubstance to be identified subsequent to excitation.
 13. Method as inclaim 12, wherein said parameters comprise: the presence or absence offluorescence, a fluorescence time greater or less than a thresholdvalue, the presence or absence of a peak at a preset wavelength and/oremission peak heights corresponding to a concentration of markers thatis greater or less than a predefined threshold value.